This invention relates to an improved magnetic clamp for releasably securing together a plurality of paper documents and the like, and a method of making such clamp. More particularly, this invention relates to an improved clamp of the type described which utilizes a pair of strip magnets that are hinged together by a U-shaped plastic strip which normally assumes a closed position in which the two magnets engage each other, or releasably clamp therebetween a plurality of sheets of paper and the like.
It has long been customary for housewives to utilize small magnets for releasably attaching notes, papers, photographs, and the like, to ferrous metal surfaces, such as for example the metal door of a refrigerator or the lie. By interposing one or more sheets of paper between the refrigerator door and the associated magnet, the magnet functions to retain the documents releasably on the door where they can be readily observed. Such use of the magnets, while providing inexpensive and simple means for displaying paper documents, nevertheless is satisfactory only for retaining one or two rather light documents against the door of a refrigerator. If too many documents are mounted beneath the magnet, the magnet not infrequently is dislodged from the door when the latter is closed, thus dislodging also the papers or documents previously secured to the door.
In the business world, office help frequently employ metal clamps for securing together a plurality of paper documents; and the clamps in turn may be suspended from a wall projection or the like. Metal clamps of the type described are rather expensive, and because of their configuration are not designed to be mounted on the plane surface of a wall or the like.
Still another type of known paper clamp has comprised two, separate magnetic strips, one of which was disposed to be adhesively secured at one side thereof to a wall or the like. Documents were then positioned over the strip which was adhered to the wall, and a second magnetic strip was then positioned over the documents and in registry with the first magnetic strip. The magnetic field extending between the registering strips then caused the documents to be gripped releasably and securely between the two magnetic strips. The disadvantage of this construction, of course, is that one of the magnetic strips can be lost or misplaced. To overcome the foregoing problem efforts have been made to couple or hinge the two magnetic strips together with a strip of transparent celluloid-type material. However, this design resulted in a paper clamp in which the material that hinged or coupled the magnetic strips together tended normally to assume a planar rather than a folded position, and thus tended to urge the magnetic strips away from each other, thereby weakening the gripping power of the two magnetic strips.
A problem common to each of the two above-noted types of magnetic paper clamps is attributable to the fact that each of the two magnetic strips of a respective clamp is made from magnetized particles arranged to extend longitudinally of the strip in parallel rows, and with the particles of one row being of one polarity (for example, north) and the adjacent row being of the opposite polarity (for example, south). For maximum clamp gripping force, it is therefore essential that the two confronting faces of the magnetic strips be in exact registry with each other when the clamp is closed, because if the two faces are laterally offset from each other, there is a corresponding reduction in flux between the strips. No such exact registry of the confronting faces of the magnetic strips was assured by prior art clamps of the type described above.
Accordingly, it is an object of this invention to provide an improved magnetic paper clamp of the type formed from a generally rigid, plastic strip which is folded into U-shaped configuration about a radiused fold located intermediate the side edges of the strip, so that a pair of strip magnetics, which are secured to the inside, confronting surfaces of the folded plastic strip, normally are maintained in registering, confronting engagement with each other.
Another object of this invention is to provide an B improved, generally U-shaped magnetic paper clamp of the type described which has on one outside surface thereof means for mounting the clamp on the surface of a wall or adjustably on a rack.
It is an object also of this invention to provide an improved method of producing a magnetic paper clamp by heat forming the two, parallel legs of a generally U-shaped plastic support member about a radiused fold line, so that the two magnetic strips supported on the legs of the folded plastic strip normally will be maintained in registering, confronting engagement with each other.
Other objects of the invention will be apparent hereinafter from the specification and from the recital of the appended claims, particularly when read in conjunction with the accompanying drawing.